<template>
  <div>
    <div class="goods">
      <div class="menu-wrapper">
        <ul ref="menuUl">
          <li class="menu-item"
              v-for="(good,index) in goods"
              :key="good.name"
              @click="selectGood(index)"
              :class="{current: currentIndex===index}"
          >
            <span class="text bottom-border-1px">
              <img class="icon" :src="good.icon" v-if="good.icon">{{good.name}}
            </span>
          </li>
        </ul>
      </div>
      <div class="foods-wrapper">
        <ul ref="foodsUl">
          <li class="food-list-hook" v-for="good in goods" :key="good.name">
            <h1 class="title">{{good.name}}</h1>
            <ul>
              <li v-for="(food,index) in good.foods"
                  :key="index"
                  class="food-item bottom-border-1px"
              >
                <div class="icon">
                  <img width="57" height="57" :src="food.icon">
                </div>
                <div class="content">
                  <h2 class="name">{{food.name}}</h2>
                  <p class="desc">{{food.description}}</p>
                  <div class="extra">
                    <span class="count">月售{{food.sellCount}}份 &nbsp &nbsp 好评率{{food.rating}}%</span>
                  </div>
                  <div class="price">
                    <span class="now">￥{{food.price}}</span>
                  </div>
                  <div class="cartcontrol-wrapper">
                    CartControl组件
                  </div>
                </div>
              </li>
            </ul>
          </li>
        </ul>
      </div>
    </div>
  </div>
</template>

<script>
  import {mapState} from 'vuex'
  import BScroll from 'better-scroll'
  export default {
    name: 'goods',
    data(){
      return {
        scrollY: 0,   // 右侧菜单的滑动距离
        Tops: [],     // 右侧分类对应的Top数组,Top是每一个分类li距离顶部的距离
      }
    },
    computed:{
      ...mapState({
        goods: state => state.shop.goods
      }),
      currentIndex(){
        const {scrollY, Tops} = this
        const index = Tops.findIndex((top,index)=>{
          return scrollY>=top && scrollY<Tops[index+1]
        })
        
        if(this.index !== index && this.menuScroll){
          this.index = index
          const li = this.$refs.menuUl.children[index]
          this.menuScroll.scrollToElement(li,300)
        }
        
        return index
      }
    },
    methods:{
      initScrolls(){
        this.menuScroll = new BScroll('.menu-wrapper',{
          click: true
        })
        this.foodScroll = new BScroll('.foods-wrapper',{
          click: true,
          probeType: 1
        })
        this.foodScroll.on('scroll',({x,y})=>{
          // console.log('scroll',x,y)
          this.scrollY = Math.abs(y)
        })
        this.foodScroll.on('scrollEnd',({x,y})=>{
          // console.log('scrollEnd',x,y)
          this.scrollY = Math.abs(y)
        })
      },
      initTops(){
        const tops = []
        let top = 0
        tops.push(top)
        const lis = this.$refs.foodsUl.children
        Array.from(lis).forEach((li)=>{
          top += li.clientHeight
          tops.push(top)
        })
        this.Tops = tops
        // console.log(this.Tops)
      },
      selectGood(index){
        //点击左边的某一个类目，右边菜单滑动到对应的类目
        // scrollTo(x, y, time, easing)
        this.scrollY = this.Tops[index]
        this.foodScroll.scrollTo(0,-this.scrollY,300)
      }
    },
    watch:{
      goods(){
        this.$nextTick(()=>{
          this.initScrolls()
          this.initTops()
        })
      }
    }
  }
  /*https://ustbhuangyi.github.io/better-scroll/doc/zh-hans*/
</script>

<style lang="stylus" rel="stylesheet/stylus" scoped>
  @import "../../../common/stylus/mixins.styl"
  .goods
    display: flex
    position: absolute
    top: 225px
    bottom: 46px
    width: 100%
    background: #fff;
    overflow: hidden
    .menu-wrapper
      flex: 0 0 80px
      width: 80px
      background: #f3f5f7
      .menu-item
        display: table
        height: 54px
        width: 56px
        padding: 0 12px
        line-height: 14px
        &.current
          position: relative
          z-index: 10
          margin-top: -1px
          background: #fff
          color: $green
          font-weight: 700
          .text
            border-none()
        .icon
          display: inline-block
          vertical-align: top
          width: 12px
          height: 12px
          margin-right: 2px
          background-size: 12px 12px
          background-repeat: no-repeat
        .text
          display: table-cell
          width: 56px
          vertical-align: middle
          bottom-border-1px(rgba(7, 17, 27, 0.1))
          font-size: 12px
    .foods-wrapper
      flex: 1
      .title
        padding-left: 14px
        height: 26px
        line-height: 26px
        border-left: 2px solid #d9dde1
        font-size: 12px
        color: rgb(147, 153, 159)
        background: #f3f5f7
      .food-item
        display: flex
        margin: 18px
        padding-bottom: 18px
        bottom-border-1px(rgba(7, 17, 27, 0.1))
        &:last-child
          border-none()
          margin-bottom: 0
        .icon
          flex: 0 0 57px
          margin-right: 10px
        .content
          flex: 1
          .name
            margin: 2px 0 8px 0
            height: 14px
            line-height: 14px
            font-size: 14px
            color: rgb(7, 17, 27)
          .desc, .extra
            line-height: 10px
            font-size: 10px
            color: rgb(147, 153, 159)
          .desc
            line-height: 12px
            margin-bottom: 8px
          .extra
            .count
              margin-right: 12px
          .price
            font-weight: 700
            line-height: 24px
            .now
              margin-right: 8px
              font-size: 14px
              color: rgb(240, 20, 20)
            .old
              text-decoration: line-through
              font-size: 10px
              color: rgb(147, 153, 159)
          .cartcontrol-wrapper
            position: absolute
            right: 0
            bottom: 12px
</style>
